Joints of the Digits

00:01 So, now, let's look at the joints of the digits.

00:04 So, here, we can see we have the metacarpophalangeal joints between the metacarpals and the proximal phalanges.

00:12 And then, we have proximal interphalangeal joints between the proximal and the middle phalanges.

00:18 And then, we have the distal interphalangeal joints between the middle and the distal phalanges.

00:23 So, here, we can see all of these and obviously, in the thumb, we only have one interphalangeal joint because you only have two phalanges in your first digit.

00:33 So, here, we've got the metacarpophalangeal joints connecting between the distal head of the metacarpal bone and the proximal end of the proximal phalanx.

00:43 Here, we can see the joint capsule and we have a number of ligaments which again, help to reinforce it. We have the lateral collateral ligament here.

00:51 We also have a palmar ligament on a palmar aspect.

00:55 Movements of these are abduction which we're familiar with when we looked at the muscles of the hand and adduction and you could see these happening at the metacarpophalangeal joints.

01:05 You also have limited amounts of rotation and circumduction and as you'd expect at the metacarpophalangeal joints, you have flexion and extension but notice how flexion is much more pronounced than extension as you form that grip. If we then look at the interphalangeal joints, these are really occurring at the distal end of the hand between the proximal and middle and distal phalanges.

01:30 And you can see each one of them has a joint capsule.

01:33 These are reinforced by some interphalangeal collateral ligaments and the movements associated with these are quite complex.

01:40 You could have flexion and you can have extension, but try to remember the organization of the muscles, the dorsal and the palmar interossei, the lumbricals that are all helping to move fingers in this direction.

01:55 So, there's quite a lot of the anatomical structures located around the joints and it's important you're familiar with the movements that help to move - that enables the upper limb to assume different positions.